A
bstract
A factorization hypothesis is tested by examining a form factor of the
ωπ
production in hadronic
B
0
→ D
∗±
ωπ
∓
decays. The form factor is compared to that from available
τ
-lepton as well ...as
e
+
e
−
data using the conserved vector current hypothesis. The difference of normalizations of form factor shapes from
B
and
τ
(
e
+
e
−
) data indicates the important role of the large
N
c
limit in QCD. Moreover, the growth of the difference between the form factors with the
ωπ
invariant mass is related to the perturbative QCD corrections of factorization. The current precision of
B
data does not allow one to find any evidence of corrections to factorization. A promising study could be performed with the Belle II and LHCb data sets.
The CMD-3 detector has begun to take data at the electron-positron collider VEPP-2000 since december 2010. The collected data sample corresponds to an integrated luminosity of 60 pb−1 in the c.m. ...energy range from 0.32 up to 2 GeV and about 50pb−1 for RUN2017. The integrated luminosity was measured by counting e+e− e+e− and e+e− γγ events, allowing additional photons in the final state. Preliminary results of the luminosity measurement are presented for various energy ranges and its accuracy is estimated to be 1%.
The cross-section of the process e+e−→π+π− has been measured using about 114000 events collected by the CMD-2 detector at the VEPP-2M e+e− collider in the center-of-mass energy range from 0.61 to ...0.96 GeV. Results of the pion form factor determination with a 0.6% systematic uncertainty are presented. The following values of the ρ- and ω-meson parameters were found: Mρ=(776.09±0.81) MeV, Γρ=(144.46±1.55) MeV, Γ(ρ→e+e−)=(6.86±0.12) keV, Br(ω→π+π−)=(1.33±0.25)%. Implications for the hadronic contribution to the muon anomalous magnetic moment are discussed.
Since 2010 the CMD-3 detector has been collecting data at the e+e− collider VEPP-2000 in the Budker Institute of Nuclear Physics. One of the main goals of experiments with CMD-3 detector is the ...precise measurement of the cross sections of the e+e− annihilation into hadrons. For a large number of processes the main source of systematic uncertainty in cross sections determination due to accuracy of polar angles determination of the tracks. Z-chamber is used for the reconstruction of the track longitudinal coordinate which is with low systematic uncertainty. The measurement of longitudinal coordinates is performed by the collecting of the charge which is induced on the strip cathodes of the Z-chamber. The algorithms of the reconstruction of cathodes clusters and calibration procedure are presented.
Monte-Carlo generator with photon jets radiation in collinear regions for the process e super(+) e super(-) arrow right gamma gamma is described in detail. Radiative corrections in the first order of ...alpha are treated exactly. Large leading logarithmic corrections coming from collinear regions are taken into account in all orders of alpha by applying the Structure Function approach. Theoretical precision of the cross section with radiative corrections is estimated to be 0.2%. This process is considered as an additional tool to measure luminosity in forthcoming experiments with the CMD-3 detector at the e super(+) e super(-) collider VEPP-2000.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The CMD-3 detector has been successfully collecting data at the electron-positron collider VEPP-2000 since December 2010. The first scan below 1 GeV for a π
+
π
−
measurement was performed in 2013. ...The collected data sample corresponds to about 18 pb
−1
of integrated luminosity in this energy range. Analysis of the
e
+
e
−
→ π
+
π
−
cross section is in progress. Status of this measurement are presented.
The CMD-3 detector started data taking at the electron-positron collider VEPP-2000 1 in December 2010. The collected data sample corresponds to an integrated luminosity of 87 pb
−1
in the c.m. energy ...range from 1.06 up to 2 GeV and 91 pb
−1
from 0.32 to 1.06 GeV. The integrated luminosity was measured by counting
e
+
e
−
→
e
+
e
−
and
e
+
e
−
→ γγ events, allowing additional photons in the final state. Preliminary results of the luminosity measurement are presented for various energy ranges and its accuracy is estimated to be 1%.
The data sample collected in 2011-2013 at the c.m.s. energies between 0.32-2 GeV with the CMD-3 detector operating at the VEPP-2000
e
+
e
−
collider is analzed. The collected data corresponds to an ...integrated luminosity about ∼ 60
pb
−1
. The techniques for determination of the integrated luminosity for each energy setting is described. Some preliminary results of the study of the processes
e
+
e
−
→
K
+
K
−
+
n
π (n = 1,2,3) with two charged kaons in the final state are presented. These processes have several intermediate states, which are important to correctly descript the angular distributions of final particles and the cross sections dependence on the energy.
CMD-3 Overview Logashenko, Ivan B.; Ignatov, F.V.; Akhmetshin, R.R. ...
EPJ Web of Conferences,
2019, Letnik:
218
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The CMD-3 detector is installed at the VEPP-2000
e
+
e
−
collider at BINP (Novosibirsk, Russia). It is a general-purpose detector, equipped with a tracking system, two crystal (CSI and BGO) ...calorimeters, liquid Xe calorimeter, TOF and muon systems. The main goal of experiments at CMD-3 is a study of exclusive modes of
e
+
e
−
→
hadrons
at energies $ \sqrt s \le $ GeV. In particular, these results provide an important input for calculation of the hadronic contribution to the muon anomalous magnetic moment.
The first round of data taking was performed in 2011–2013, when about 60 1/pb were taken in the center-of-mass (c.m.) energy range from 0.32 to 2.0 GeV. Here we present a survey of results of data analysis.
Between 2013 and 2016 the collider and the detector were upgraded. The data taking resumed by the end of 2016. In the first run after the upgrade about 50 1/pb were collected at the energy range between 1.28 and 2.007 GeV. We discuss the upgrade and the first preliminary results from the new data.
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